Most waders are constructed with a rigid, non-stretch woven fabric, such as nylon (usually taffeta), cotton (sheeting), or polyester. The fabric is then coated with a waterproof material such as polyvinylchloride, polyurethane, or material or synthetic rubber. The fabric is the supporting material for the waterproof coating. The waterproof coating can be used either on the inside or the outside of the garment. Knitted fabrics are not widely used in the construction of waders in that waterproof coatings do not adhere well to knitted fabrics.
In waders, the legs of the wader are attached to a bootie. Due to the attachment of the leg to the bootie and the non-stretch properties of the woven fabric support material, the woven fabric support material does not allow the leg to move upwards when the knee is bent during walking motion. Accordingly, additional inseam material, greater than the user's actual inseam measurement, is required. Otherwise the user could bend their knee.
Therefore, it is common practice in the construction of a pair of waders made from a rigid, non-stretch woven fabric to add several inches of material, typically three to seven inches of inseam material to accommodate the walking motion. This adds additional expense to the garment and to do not so would make the product unusable.
In U.S. Pat. No. 4,117,552 to Simpson, the leg portions of a protective clothing garment include excess fabric over the outside knee and elbow joints by means of additional material tucks to aid in mobility of the garment. The excess fabric coincides with the joint region for all joint positions in a particular size.
In U.S. Pat. No. 4,509,213 to Harvey, a plurality of accordeon pleats extend transversely across a front portion of each legging of a rain cover for motorcyclist's legs in the region of the knee. When the knee is flexed, the accordeon pleats open and no upward pull is exerted on the remainder of the garment. The accordeon pleats are formed by an extra length of material at the knee level of the front panel.